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1956 A. L. STEELE CENTRIFUGAL ACTUATOR Filed Jan. 13, 1954 m E .E N 2 R E m Hr T An m5 4 MM United States Patent CENTRIFUGAL ACTUATOR I Arlo L. Steele, New Carlisle, Ohio, assignor to Robbins & Myers Inc., Springfield, Ohio, a corporation of Ohio Application January 13, 1954, Serial No. 403,758

9 Claims. (Cl. 264--15) This invention relates to a centrifugal actuator and more particularly to a device adapted to be mounted upon the shaft of an electric motor or the like and arranged when the motor attains a certain speed to exert a snap action for actuating a switch or the like. This application is a continuation-in-part of my copending application, Serial No. 312,193 filed September 30, 1952, now abandoned.

Centrifugal actuators for this general purpose are well known and have been in use for many years. They have been uniformly complex and expensive to manufacture and have been subject to failure for any one of a number of reasons.

It is an object of the present invention to provide a centrifugal actuator which will be inexpensive in construction, simple in operation, and not likely to get out of adjustment. 7

It is another object of the invention to provide a centrifugal actuator as outlined in which the speed at which the action takes place can be adjusted without the necessity of special tools.

It is yet another object of the invention to provide an actuator which when the required speed is attained operates with a snap action so that the device is useful for actuating switches to avoid arcing.

These and other objects of the invention which will be pointed out in greater detail hereinafter or which will be apparent to one skilled in the art upon reading the specifications, I accomplish by that certain construction and arrangement of parts of which I shall now describe an exemplary embodiment.

Reference is made to the drawing forming a part hereof and in which:

Figure 1 is a plan view of the device according to the invention, as seen on line 11 of Figure 2.

Figure 2 is a cross-sectional view of the same taken on the line 2-2 of Figure 1.

Figure 3 is a fragmentary cross-sectional view taken on the line 33 of Figure 1.

Figure 4 is a view similar to Figure 3 but showing the device in a different position.

Figure 5 is a perspective view of the main frame portion of the device.

Figure 6 is a perspective view of the weighted arm portion of the device.

Figure 7 is a perspective view of the actuator element.

Figure 8 is a fragmentary cross-sectional view taken on the line 88 of Figure 6.

Briefly in the practice of the invention, I provide a frame element arranged to be secured axially to the shaft of an electric motor or the like. Pivotally mounted upon this frame element is a weighted arm which is arranged to swing outwardly under the influence of centrifugal force. The weighted arm carries bearing shoulders for the actu ator element which is held in position on the arm by means of a spring so that the pivot point of the actuator element is to one side of the spring axis. As the speed of the device increases the weighted arm swings outwardly and brings the pivot point of the actuator member across the axis of the spring so that a snap action results.

Referring now in greater detail to the drawing, I have indicated a fragment of an electric motor or the like at 10 in Figures 1 to 4 inclusive. The motor shaft is indi cated at 11. Secured to the motor shaft as by means of a screw 12 is a frame element indicated generally at 13 and shown in detail in the perspective view of Figure 5.

Referring now to Figure 5, the frame 13 may consist of a base portion 14 provided with the hole 15 for the screw 12. Upstanding side walls 16 and 17 are provided and a spring attaching lug 18 also extends at right angles from the portion 14. The members 16 and 17 are provided with holes 19 and 20 which serve as bearings for the pivoting of the weighted arm to be described hereinafter. Struck out ears are provided at 21 and 22 to act as stops for the weighted arm. Additional ears are provided at 23 and 24 to provide stops for the weighted arm at the other extreme of its movement. A pin 52 is provided to restrict travel of the actuator element 38 in a clockwise direction.

The weighted arm is shown in detail in Figure 6 and is indicated generally at 26. It is provided with the pintles 2'7 and 28 which are arranged to seat in the holes 19 and 29 to provide a pivot axis for the weighted arm. The Weighted arm may be provided with the right angle portion 29 to which a desired number of weights may be attached. The member 26 is also provided with the right angle portions 30 and 31 which are configured to provide the shoulders 32 and 33 on which the actuator element is pivoted.

A longitudinal slot 34 is provided in the member 26, and a plurality of transverse grooves 35.

The actuator element itself is shown in detail in Figure 7 and is generally U shaped and is provided with the arcuate portions 36-37 which are adapted to seat on the shoulders 32 and 33 of the member 26. The actuator element which is indicated generally by the numeral 38 has a spring attaching lug 39 and an actuator button 40.

In assembly, the member 26 is assembled as described above so that at one extreme of movement it abuts the ears 21 and 22 as shown in Figure 2, and at its other extreme it abuts the ears 23 and 24 as shown in Figure 4. It will be understood that in the showing of Figures 2, 3 and 4 under the influence of centrifugal force the weighted arm 26 swings upwardly in those figures. A spring 41 is provided, one end of which is secured to the portion 18 of the frame 13 and on the other end of which is secured to the weighted arm. It is secured by passing the eye or loop of the spring through the slot 34 and engaging it by means of a pin 42 resting in one of the grooves 35. Thus by positioning the pin 42 in selected ones of the grooves 35, the moment arm of the spring can be varied so as to vary the rotational speed which will cause the actuator member to function.

The actuator element 38 is mounted as described with the portions 36 and 37 engaging the shoulders 32 and 33 as can be clearly seen in Figures 2, 3 and 4. A spring 43 is secured at one end to the spring attachment lug 39 and at its other end to the weighted arm 26 substantially on the pivot axis thereof. As best seen in Figure 8 a pin 44 passes through the eye of the spring 43 and is seated in a groove 35a.

From a consideration of Figure 2, it will be clear that the axis of the spring 43 between the pin 44 and the lug 39 lies to the left of the pivot point between the actuator element 38 and the shoulders 32 and 33. This is the position of the Figures 2 and 3.

As the device is rotated and the weighted arm 26 swings upwardly in the figures, the shoulders 32-33 swing clockwise as well, about the pivot point 28 until the pivot point of the elements 36-37 against the shoulders 32'33 passes across the axis of the spring 43 as shown in Figure 4. The actuator element 38 .is prevented from movement toward the .left -by the pin 52, so that the arcuate portions 36, 37 slide on the shoulders 32, 33 until the pivot points pass the axis of the spring, whereupon the spring 43 produces a snap movement of the actuator elemerit 38 in a counterclockwise direction to the position shown in Figure 4. 50-51 indicate contacts of a switch or the like and it will be observed that in Figure 4 the actuator element has caused the contacts 50-51 to be closed and it Will be clear that this has been done by a snap action.

It will also be observed that the button 40 referred to above is substantially on the axis of the shaft 11 so that friction between the member 40 and the contact arm is minimized.

From what has been said above, it will be seen that the centrifugal actuator herein described is extremely simple in construction and that the speed at which it functions may be adjusted without the use of special tools by simply moving the pin 42 to one or another of the various grooves 35.

It will be clear that numerous modifications may be made without departing from the spirit of the invention and 1' therefore do not intend to limit myself except as set forth in the claims which follow.

Having now fully described the invention, what I claim as new and desire to secure by Letters Patent is:

l. A centrifugal actuator comprising a frame adapted to be rotated about an axis of rotation, a weighted arm pivoted to said frame on an axis normal to said axis of rotation, an actuator element having a pivotal bearing on said weighted arm about an axis parallel to said first named axis but eccentric thereto, a spring secured at one end to said weighted arm substantially on its pivot axis, and at the other end to said actuator element beyond said pivotal bearing, an abutment for said arm disposed on said frame adjacent said arm to hold said arm and actuator element, when at rest, with said eccentric axis to one side of the axis of said spring, and an abutment for said actuator element'on said frame adjacent said actuator element preventing substantial movement thereof with said weighted arm, whereby when said device is rotating and said weighted arm pivots as a result of centrifugal force, said eccentric axis crosses the axis of said spring, whereby said actuator element is given a snap actuating movement.

2. A device according to claim 1, wherein a spring is secured at one end to said frame and at its other end to said weighted arm, to control the effective weight of said arm.

attachment of said last named spring to said weighted arm is adjustable with relation to the pivot axis of said weighted arm, to vary the effective weight to said arm.

4. A device according to claim 3, wherein said Weighted arm has a slot normal to its pivot axis, and a series of spaced grooves transversely disposed with respect to said slot, and wherein the end of said spring which is secured to said weighted arm is secured by a pin seated in one of said transverse grooves and passing through the spring eye which extends through said slot.

5. A device according to claim 1, wherein said actuator element is provided with an actuator button substantially on the axis of rotation of said actuator.

6. A centrifugal actuator comprising a frame adapted to be rotated about an axis of rotation, a weighted arm pivoted to said frame, a spring secured at one end to said frame and at its other end to said arm to resist the outward swing of said arm due to centrifu al force, an extension on said arm disposed at an angle to said arm and providing pivotal shoulders, an actuating element having forks bearing on said shoulders and a spring extending between said arm and said actuating element beyond said forks, holding said actuating element in place, said pivotal. shoulders and forks, when said actuator is at rest, being disposed at one side of the axis of said last ientioned spring, and said shoulders being movable, when said arm is swinging outwardly, to point to the other side of the axis of said last mentioned spring and an abutment on said frame adjacent to said actuating element to prevent substantial movement thereof with said weighted arm, whereby there is produced a snap action of said actuating element.

7. A device according to claim 6, wherein the point of attachment of said first mentioned spring to said weighted arm is adjustable with relation to the pivot axis or" said weighted arm, to vary the eifective weight of said arm.

8. A device according to claim 7, wherein said weighted arm has a slot normal to its pivot axis, and a series of spaced grooves transversely disposed with respect to said slot, and wherein the end of said spring which is secured to said weighted arm is secured by a pin seated in one of said transverse grooves and passing through the spring eye which extends through said slot.

9. A device according to claim 6 wherein said actuating element is provided with an actuator button substantially on the axis of rotation of said actuator.

References Cited in the file of this patent UNITED STATES PATENTS 

